Half to thomas m



(No Model.) a Sheet S- SheetI.

- W. D. THO-MAS;

STEAM ENGINE VALVE GEAR.

Patented Feb. 19, 1884;

(No MOdel.) a Sheets-Shea 2.

W. D. THOMAS, STEAM ENGINE VALVE GEAR. v No. 293,686. Patented eb. 19,1884.

Hllllllfillll'l munun IHH'IIH (No'ModeL) I 3 fihee't sheet 3.

' W D. THOMAS STEAM ENGINE VALVE GEAR.

, s Paten-tedP-e b 19', 1884.

N. PETERS. Fhulmlilhognphcn WJSHIIQIMI. n c.

UNITED STATES PATiENT ()FFIQE.

WILLIAM D. THOMAS, OF PITTSBURG, PENNSY LVANIA, ASSIGNOR OF ONE- HALF TO THOMAS M. HERRIOTT AND QAVETT & McKNIGHT, ALL OF SAME PLACE.

STEAM ENGlNE VALVE-GEAR.

SPECIFICATION forming part Of Letters Patent N; 293,686, dated. February 19, 1884.

I Application filed September 19,1sea. (No model.)

T0 at whom it may concern.-

Be it known that I, WILLIAM D. THOMAS, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Steam-Engine Valve-Gears; and I do hereby declare the following to be a full, clear, and exact descrip tion thereof.

My invention relates to apparatus for operro ating the valves of steam-engines, having special reference to what are known on the western waters as river-engines or mill-engines. Its special object is to improve the construction of the variable cut-offs employed I 5' with these engines, so as to render them capable of accurate regulation, and to furnish cutoff apparatus which is positive in motion and simple in construction.

It consists in certain improvements in the construction of the apparatus hereinafter specifically described and claimed. I

, To enable others skilled in the art to make and use my invention, I will describe its construction and operation, referring to the ac- 2 5 eompanying drawings, in which- Figure 1 is a face view of a marine or mill engine illustrating the apparatus, showing the gear in one position. Fig. 2 is a like view showing the gear in another position. Fig. 3

is an enlarged face view of the cut-off apparatus. Fig. 4 is a rear view of the pivoted slide frame, the wabblerbeing shown in dotted lines to further illustrate the same. Fig. 5 is a side view of the cut-off apparatus. Fig. 6 is a top view of the same; and Fig. 7 is a perspective view, the movements of the parts in varying the cut-off being illustrated in dotted lines.

Like letters of reference indicate like parts in each.

In the drawings the invention is illustrated in connection with an ordinary steamboat'or mill engine, A being the cylinder, B the piston-rod, and O the pitman. The engine is provided with the ordinary steam supply and I exhaust pipes, the supply-pipe D being shown,

and the supply-valves d d in the supply-pipe operated by the levers (1 (1 The steam-exhaust pipe and exhaust valves are back of these parts, the exhaust-valves being operated by the lovers a a. l

J ournaled in suitable bearings, and extend .ing centrally across the top of the steam-cylinder, is the shaft 6, to which the supply-lifter E is rigidly secured, the shaft being turned by the crank e, which is connected by the rod 6*? to the cut-off apparatus, as hereinafter described. The exhaust-valve rods are operated by the rod z" through the crank f, secured to a shaft journaled above side of the shaft 6, and connected by means of a link to the exhaust-lifter F, journaled on said shaft 2. These parts are of the construction generally em-' ployed on steam-engines, and are simply referred to to further illustrate my invention.

J ournaled on suitable bearing, 0, on the engine-frame in front of the slides c of the pitman, is my improved variable cut-off. This cut-off is formed of the pivoted slide-frame G, which is rigidly secured to the shaft mounted in said bearings 0, and the wabbler H, which is journaled on said shaft g by means of the sleeve h. The wabbler is connected by the cam-rodi to the exhaust-box, fitting around the exhaust-cam on the pitman-shaft, these parts being of the usual construction and not being shown. The wabbler is also connected by the rod 1' to the crank f of the exhaustvalve apparatus, the rod t" being a continua tion of the cam-rod t, so that as the exhaustvalves are opened and closed by the reciprocating motion of said camrods, a corresponding reciprocating motion is imparted to the wabbler H, causing it to swing or wabble at intervals on its journal.

In the wabbler H are the open slots or guides k'7cone on each sidethese guide-slots extending for the entire length of the wabbler. In these guide-slots are the sliding cutoff blocks Z I, which fit the slots neatly, and are formed wedge shape, or inclined at their upper ends, the wedgefaces being on the inner side of the blocks, as at P.

3 Between the guide-slots k k in the upper part of the wabbler is the guide-slot m, fitting within which is the sliding block m, this block being about the same length as the guideslot m, and being held within this slot by the cutoff blocks 1 Z, when they are raised so that their parallel parts are opposite the ends of the guide m, but the sliding block entering either guide-slot r or it when the wedge-face '1 of either cut-off block is-opposite or below the end of the slot m. The cut-oft blocksZ Z and sliding block at are held in their respective slots by lips along the edges of the slots. The sliding block at is connected by the rod 0 to the crank c, by which the supply-lifter E is operated. Thepivotedslide-frameGisformed of an upright body, a, at the base of which, below the pivoted point 9, the rod 1), by which it is vibrated, is secured, and the arms a a extending downward diagonally from the body at about the center thereof.

I11 the body '12 of the frame, above the pivotal point, is the slot T, which extends entirely through the body, and has the slide '1- mounted therein, to the front of which is pivoted the rod .9, which is connected below the slide-frame to the lever S, pivoted on the engine-frame and connected by the rod .9 to the varying-lever s", catching in a ratchet, 8. By the movement of this levers, the slide 2' can be raised and lowered in the slot 0' of the slide-frame to vary the cutoff, as hereinafter described.

In the rear of each diagonal arm a 11 of the frame G is a guide or open slot, 15, having a slide, i, secured therein, and these slides tare connected to the rear of the slide rin thebody n by links a. One slide, 2, is also connected by the rod 1) to the cut-off block Z of the wabbler, and the other slides iby the rod 1; to the cut-off block Z thereof, so that when the pivoted frame G'is vibrated by the rod 1) across the wabbler by means of these .rods 1) o it causes the cut-off blocks to slide up and down in the wabbler. This is more clearly understood from the rear view of the frame G, Fig. 4. The desired reciprocating vibration of the frame G is imparted to it through the rod 1) by means of asuitable cam and cam-box (not shown) and the pitman-shaft of the engine, or by other suitable means.

It is evident that by drawing the cut-off blocks Z Z up and down in the wabbler they will hold the sliding block at for a longer or shorter time within its slot m, and that they will thus hold the rod 0* of the supply-valve apparatus stationary in the wabbler for a greater or less portion of the stroke. This is accomplished by means of the varying or cutoff lever s, which raises and lowers the slide 9' within the pivoted frame G, this slide, by means of the rods 1!, slides t, and rodst-vraising and lowering the cut-off blocks'l l in the wabbler.

The different positions of the apparatus are shown in the several views, the apparatus being arranged for full stroke in full linesin Fig. 7 to cut off at one-half the strokein Figs. 1 to 6, and to cut off at one-quarter stroke in dotted lines in Fig. 7.

\V hen the engine is in operation, the cam-rod 1' draws the wabbler over (for example) to the right, and at the same time through the rod 2', crank f, exhaust-lifter F, and lever a it opens the left exhaust-valve. As the sliding block m is held stationary by the cutoff block I, as the wabbler is drawn over,it draws the rod c,

and through the crank c, supply-lifter E, and lever d it opens the right supply-valve, d, as shown in Fig. 1. The exhaust and supply valves are thus opened, and the steam forces the piston to the left, and the wabbler remains stationary during the second and third quarter of the stroke. \Vhile the wabbler is in this position, the pivoted frame G is vibrated by the rod j), as before described, and thus draws down the left cut-oft block, Z, until it passes the end of the sliding block m, leaving it free to move across the guide-slot,and at the same time raises the other cut-off block, Z, in its slot, closing the other end of the guide-slot m. As the valve-lever d rests on the supplylifter, as soon as the cut-off block Z is drawn down, as the rod e no longer supports the lifter, but is free to move, the weight of the valve-lever presses down the supply-lifter E, and through the rod 0 draws the cutoff block across the slot 7; above the wedge-block Z, thus cutting off the supply of steam, as shown in Fig. 2. As the upper part of the cut-off block is inclined or wedge-shaped, the sliding block will travel up this inclined face and close the valve without a jar, thus, as it were, cushioning the valve and preventing jar to the machinery. At the end of the stroke the cam on the pitlnan-shaft causes the rodt' to carry the wabbler over to the left, and at the same time, through the rod '13 and other connections,open the right exhaust valve, and as the water moves to the left the sliding block m comes against the cut-off block l at the other side of the wabbler, and is carried with it, and through the rod 6* and its connections opens the left supply-valve, d, the valve remaining open until the cutoff block Z is drawn aside by the pivoted frame, as above deseribed,when the supply-valve is closed, the operation being thus continued through each stroke of the piston.

By raising the cut-off blocks in the wabbler, as above described, to the highest point, as shown in Fig. 7, the'blocks Z I will hold the sliding block at stationary with the wabbler, and thus cause the supply-valve rod to move with the exhaust-valve rod during the entire.

stroke and steam to be supplied during the full stroke. By lowering the cut-off blocks in the wabbler, the apparatus may be varied to cut off the steam at any desired part of the stroke.

Vhere my improved cut-off is employed with slide-valve engines,its operation is practicallyihe same, except that the pivoted frame is vibrated at a different time with relation to the wabbler, it being arranged to cut off the steam by the raising of the cut-off blocks, thus closing the supply-valve.

\Vhat I claim as my invention, and desire to secure by Letters Patent, is

1. In steam-engine valve-gear, the combination, with apparatus moving with the exhaust-valve cam-rod, of a slide therein e011- neeted with the supply-valves, and a frame pivoted below said exhaust-valve cam-rod and adapted byits vibration to free said"slide,substantially as set forth.

2. In cut-off apparatus, the combination of a wabbler connected to the exhaust-valve cam-rod, and having a sliding block mounted therein, connected with the supply-valves, and a frame pivoted in front of said wabbler, and adapted by its vibration to. free said sliding block, substantially as and for the purposes set forth. I

3'. In cut-off apparatus, the wabbler H, connected to the exhaust-valve cam-rod, and having the sliding block m and cut-off blocks ZZ mounted therein, in combination with the pivoted frame G, having rods connected to said cut-off blocks, substantially as and for the purposes set forth.

4. In cut-off apparatus, the pivoted wabbler H, provided with the sliding block m, connected with the supply-valves, in combination with the sliding cut-off blocksl l, operated by suitable apparatus to control the motion of said block m, substantially as and for the purposes set forth.

5. In cut-off apparatus, the pivoted wabbler H, provided with the sliding block m, connected with the supply-valve apparatus, in combination with cut-off blocks Z Z, sliding within said wabbler, and having inclined upper faces, Z substantially as and for the purposes set forth.

, 6. In cut-off apparatus, the pivoted frame G, having the arms n w, said arms having slides t, mounted in suitable guides, in combination with means for varying the position of the slides inthe arms, substantially as and for the purposes set forth.

7. In cut-ofi apparatus, the pivoted frame G, having the vertically-moving slide r, in

combination with the rod 8, and suitable means for varying the position of the slide in the frame, substantially as and for the purposes set, forth. I

8. In cut-off apparatus, the pivoted frame G, formed of the body n, having the slide r and arms n if, having the slides t, in combination with links a, and suitable means for adjusting said slides in the frame substantially as and for the purposes set forth.

9. In cut-off apparatus, the combination,

-having the slides r t t, links a, connecting said slides, and rods on, connecting cut-off blocks and the slides t t, substantially as and for the purposes set forth.

In testimony whereof I, the said WILLIAM D. THOMAS, have hereunto set my hand.

, WILLIAM D. THOMAS.

Witnesses:

JAMES I. KAY, F. G. KAY. 

